import java.util.Scanner;

public class java02 {

    public static void main(String[] args) {

        Scanner in = new Scanner(System.in);

        System.out.println("请输入第一个坐标点：");

        int x1 = in.nextInt();

        int y1 = in.nextInt();

        System.out.println("请输入第二个坐标点：");

        int x2 = in.nextInt();

        int y2 = in.nextInt();

        double distance = (double) Math.sqrt(Math.abs((x1 - x2)*(x1 - x2))+Math.abs((y1 - y2)*(y1 - y2)));

        System.out.println(String.format("两点间距离是："+"%.2f",distance));

    }
}
